Commercial-type lawn mowers may include a mower deck having multiple rotary cutting blades positioned therein. Common classifications of mower decks include a mulching deck, a side discharge deck, a rear discharge deck or a bagging deck depending upon the manner in which the cut grass cuttings or clippings are handled or directed. When a mower is of the side discharge deck type, the grass clippings are discharged out a side opening of the deck. The prior art has previously provided flow control and mulch baffles which are attached to the underside of the mower deck.